30e04bcfa8
5 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Abhradeep Chakraborty
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761416ef91 |
bitmap-lookup-table: add performance tests for lookup table
Add performance tests to verify the performance of lookup table.
`p5310-pack-bitmaps.sh` contain tests with and without lookup table.
`p5312-pack-bitmaps-revs.sh` contain same tests with and without
lookup table but with `pack.writeReverseIndex` enabled.
Lookup table makes Git run faster in most of the cases. Below is the
result of `t/perf/p5310-pack-bitmaps.sh`.`perf/p5326-multi-pack-bitmaps.sh`
gives similar result. The repository used in the test is linux kernel.
Test this tree
-----------------------------------------------------------------------
5310.4: enable lookup table: false 0.01(0.00+0.00)
5310.5: repack to disk 320.89(230.20+23.45)
5310.6: simulated clone 14.04(5.78+1.79)
5310.7: simulated fetch 1.95(3.05+0.20)
5310.8: pack to file (bitmap) 44.73(20.55+7.45)
5310.9: rev-list (commits) 0.78(0.46+0.10)
5310.10: rev-list (objects) 4.07(3.97+0.08)
5310.11: rev-list with tag negated via --not 0.06(0.02+0.03)
--all (objects)
5310.12: rev-list with negative tag (objects) 0.21(0.15+0.05)
5310.13: rev-list count with blob:none 0.24(0.17+0.06)
5310.14: rev-list count with blob:limit=1k 7.07(5.92+0.48)
5310.15: rev-list count with tree:0 0.25(0.17+0.07)
5310.16: simulated partial clone 5.67(3.28+0.64)
5310.18: clone (partial bitmap) 16.05(8.34+1.86)
5310.19: pack to file (partial bitmap) 59.76(27.22+7.43)
5310.20: rev-list with tree filter (partial bitmap) 0.90(0.18+0.16)
5310.24: enable lookup table: true 0.01(0.00+0.00)
5310.25: repack to disk 319.73(229.30+23.01)
5310.26: simulated clone 13.69(5.72+1.78)
5310.27: simulated fetch 1.84(3.02+0.16)
5310.28: pack to file (bitmap) 45.63(20.67+7.50)
5310.29: rev-list (commits) 0.56(0.39+0.8)
5310.30: rev-list (objects) 3.77(3.74+0.08)
5310.31: rev-list with tag negated via --not 0.05(0.02+0.03)
--all (objects)
5310.32: rev-list with negative tag (objects) 0.21(0.15+0.05)
5310.33: rev-list count with blob:none 0.23(0.17+0.05)
5310.34: rev-list count with blob:limit=1k 6.65(5.72+0.40)
5310.35: rev-list count with tree:0 0.23(0.16+0.06)
5310.36: simulated partial clone 5.57(3.26+0.59)
5310.38: clone (partial bitmap) 15.89(8.39+1.84)
5310.39: pack to file (partial bitmap) 58.32(27.55+7.47)
5310.40: rev-list with tree filter (partial bitmap) 0.73(0.18+0.15)
Test 4-15 are tested without using lookup table. Same tests are
repeated in 16-30 (using lookup table).
Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Taylor Blau
|
bf4a60874a |
p5326: generate pack bitmaps before writing the MIDX bitmap
To help test the performance of permuting the contents of the hash-cache when generating a MIDX bitmap, we need a bitmap which has its hash-cache populated. And since multi-pack bitmaps don't add *new* values to the hash-cache, we have to rely on a single-pack bitmap to generate those values for us. Therefore, generate a pack bitmap before the MIDX one in order to ensure that the MIDX bitmap has entries in its hash-cache. Since we don't want to time generating the pack bitmap, move that to a non-perf test run before we try to generate the MIDX bitmap. Likewise, get rid of the pack bitmap afterwords, to make certain that we are not accidentally using it in the performance tests run later on. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
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Taylor Blau
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97b89c8150 |
p5326: don't set core.multiPackIndex unnecessarily
When this performance test was originally written, `core.multiPackIndex`
was not the default and thus had to be enabled. But now that we have
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Taylor Blau
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2082224f17 |
p5326: create missing 'perf-tag' tag
Some of the tests in test_full_bitmap rely on having a tag named perf-tag in place. We could create it in test_full_bitmap(), but we want to have it in place before the repack starts. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
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Taylor Blau
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2d59597333 |
p5326: perf tests for MIDX bitmaps
These new performance tests demonstrate effectively the same behavior as
p5310, but use a multi-pack bitmap instead of a single-pack one.
Notably, p5326 does not create a MIDX bitmap with multiple packs. This
is so we can measure a direct comparison between it and p5310. Any
difference between the two is measuring just the overhead of using MIDX
bitmaps.
Here are the results of p5310 and p5326 together, measured at the same
time and on the same machine (using a Xenon W-2255 CPU):
Test HEAD
------------------------------------------------------------------------
5310.2: repack to disk 96.78(93.39+11.33)
5310.3: simulated clone 9.98(9.79+0.19)
5310.4: simulated fetch 1.75(4.26+0.19)
5310.5: pack to file (bitmap) 28.20(27.87+8.70)
5310.6: rev-list (commits) 0.41(0.36+0.05)
5310.7: rev-list (objects) 1.61(1.54+0.07)
5310.8: rev-list count with blob:none 0.25(0.21+0.04)
5310.9: rev-list count with blob:limit=1k 2.65(2.54+0.10)
5310.10: rev-list count with tree:0 0.23(0.19+0.04)
5310.11: simulated partial clone 4.34(4.21+0.12)
5310.13: clone (partial bitmap) 11.05(12.21+0.48)
5310.14: pack to file (partial bitmap) 31.25(34.22+3.70)
5310.15: rev-list with tree filter (partial bitmap) 0.26(0.22+0.04)
versus the same tests (this time using a multi-pack index):
Test HEAD
------------------------------------------------------------------------
5326.2: setup multi-pack index 78.99(75.29+11.58)
5326.3: simulated clone 11.78(11.56+0.22)
5326.4: simulated fetch 1.70(4.49+0.13)
5326.5: pack to file (bitmap) 28.02(27.72+8.76)
5326.6: rev-list (commits) 0.42(0.36+0.06)
5326.7: rev-list (objects) 1.65(1.58+0.06)
5326.8: rev-list count with blob:none 0.26(0.21+0.05)
5326.9: rev-list count with blob:limit=1k 2.97(2.86+0.10)
5326.10: rev-list count with tree:0 0.25(0.20+0.04)
5326.11: simulated partial clone 5.65(5.49+0.16)
5326.13: clone (partial bitmap) 12.22(13.43+0.38)
5326.14: pack to file (partial bitmap) 30.05(31.57+7.25)
5326.15: rev-list with tree filter (partial bitmap) 0.24(0.20+0.04)
There is slight overhead in "simulated clone", "simulated partial
clone", and "clone (partial bitmap)". Unsurprisingly, that overhead is
due to using the MIDX's reverse index to map between bit positions and
MIDX positions.
This can be reproduced by running "git repack -adb" along with "git
multi-pack-index write --bitmap" in a large-ish repository. Then run:
$ perf record -o pack.perf git -c core.multiPackIndex=false \
pack-objects --all --stdout >/dev/null </dev/null
$ perf record -o midx.perf git -c core.multiPackIndex=true \
pack-objects --all --stdout >/dev/null </dev/null
and compare the two with "perf diff -c delta -o 1 pack.perf midx.perf".
The most notable results are below (the next largest positive delta is
+0.14%):
# Event 'cycles'
#
# Baseline Delta Shared Object Symbol
# ........ ....... .................. ..........................
#
+5.86% git [.] nth_midxed_offset
+5.24% git [.] nth_midxed_pack_int_id
3.45% +0.97% git [.] offset_to_pack_pos
3.30% +0.57% git [.] pack_pos_to_offset
+0.30% git [.] pack_pos_to_midx
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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